BELGRADE, Serbia-Montenegro (AP) _ Loyalists of Slobodan Milosevic were poised to win at least one city Sunday as Serbs voted for mayors and other municipal posts in runoff elections.

The trouble-prone Balkan republic was electing mayors for four of its largest cities, including the capital, Belgrade, and Novi Sad, a major provincial captial.

In those races, candidates from the ultranationalist Serbian Radical Party _ which governed Serbia together with Milosevic _ were running neck-and-neck against pro-Western members of the Democratic Party.

Voters were also choosing town council heads in 129 municipalities and members for the parliament in the province of Vojvodina, where Novi Sad is located, after the Sept. 19 first round of voting produced no clear winner.

The vote is important because victories by hard-liners could set back Serbia's efforts to join the European Union and NATO _ goals advocated by reformists ever since the pro-democracy movement toppled Milosevic, the former president of Yugoslavia, Serbia-Montenegro's predecessor.

``We must not make a single political step that would take us away from our goal of joining the European Union,'' Tadic said after casting his ballot.

After more than a decade marked by his nationalist war campaigns and bloody ethnic warfare in the Balkans during the 1990s, Milosevic was ousted in a massive revolt in October 2000, and extradited a year later for trial to the U.N. war crimes tribunal at The Hague, Netherlands.

But Serbia is still struggling to recover from Milosevic-era isolation and international sanctions.

Profiting from widespread disillusionment over a slumping economy and slow reforms, the Radicals have made substantial gains in recent years. They are the largest single party in the Serbian parliament, and as such, a strong opposition to the centrist government of Prime Minister Vojislav Kostunica.

The Radicals are particularly strong in their bid for the post of mayor in Novi Sad, the capital of the northern Vojvodina province, where the party's Maja Gojkovic garnered 42.2 percent of votes.

Tensions have mounted in Vojvodina recently between majority Serbs and minority ethnic Hungarians, after a series of incidents targeted ethnic Hungarians.